[linux.git] / crypto / dh_helper.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) 2016, Intel Corporation
 * Authors: Salvatore Benedetto <[email protected]>
 */
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/err.h>
#include <linux/string.h>
#include <crypto/dh.h>
#include <crypto/kpp.h>

#define DH_KPP_SECRET_MIN_SIZE (sizeof(struct kpp_secret) + 3 * sizeof(int))

static inline u8 *dh_pack_data(u8 *dst, u8 *end, const void *src, size_t size)
{
	if (!dst || size > end - dst)
		return NULL;
	memcpy(dst, src, size);
	return dst + size;
}

static inline const u8 *dh_unpack_data(void *dst, const void *src, size_t size)
{
	memcpy(dst, src, size);
	return src + size;
}

static inline unsigned int dh_data_size(const struct dh *p)
{
	return p->key_size + p->p_size + p->g_size;
}

unsigned int crypto_dh_key_len(const struct dh *p)
{
	return DH_KPP_SECRET_MIN_SIZE + dh_data_size(p);
}
EXPORT_SYMBOL_GPL(crypto_dh_key_len);

int crypto_dh_encode_key(char *buf, unsigned int len, const struct dh *params)
{
	u8 *ptr = buf;
	u8 * const end = ptr + len;
	struct kpp_secret secret = {
		.type = CRYPTO_KPP_SECRET_TYPE_DH,
		.len = len
	};

	if (unlikely(!len))
		return -EINVAL;

	ptr = dh_pack_data(ptr, end, &secret, sizeof(secret));
	ptr = dh_pack_data(ptr, end, &params->key_size,
			   sizeof(params->key_size));
	ptr = dh_pack_data(ptr, end, &params->p_size, sizeof(params->p_size));
	ptr = dh_pack_data(ptr, end, &params->g_size, sizeof(params->g_size));
	ptr = dh_pack_data(ptr, end, params->key, params->key_size);
	ptr = dh_pack_data(ptr, end, params->p, params->p_size);
	ptr = dh_pack_data(ptr, end, params->g, params->g_size);
	if (ptr != end)
		return -EINVAL;
	return 0;
}
EXPORT_SYMBOL_GPL(crypto_dh_encode_key);

int __crypto_dh_decode_key(const char *buf, unsigned int len, struct dh *params)
{
	const u8 *ptr = buf;
	struct kpp_secret secret;

	if (unlikely(!buf || len < DH_KPP_SECRET_MIN_SIZE))
		return -EINVAL;

	ptr = dh_unpack_data(&secret, ptr, sizeof(secret));
	if (secret.type != CRYPTO_KPP_SECRET_TYPE_DH)
		return -EINVAL;

	ptr = dh_unpack_data(&params->key_size, ptr, sizeof(params->key_size));
	ptr = dh_unpack_data(&params->p_size, ptr, sizeof(params->p_size));
	ptr = dh_unpack_data(&params->g_size, ptr, sizeof(params->g_size));
	if (secret.len != crypto_dh_key_len(params))
		return -EINVAL;

	/* Don't allocate memory. Set pointers to data within
	 * the given buffer
	 */
	params->key = (void *)ptr;
	params->p = (void *)(ptr + params->key_size);
	params->g = (void *)(ptr + params->key_size + params->p_size);

	return 0;
}

int crypto_dh_decode_key(const char *buf, unsigned int len, struct dh *params)
{
	int err;

	err = __crypto_dh_decode_key(buf, len, params);
	if (err)
		return err;

	/*
	 * Don't permit the buffer for 'key' or 'g' to be larger than 'p', since
	 * some drivers assume otherwise.
	 */
	if (params->key_size > params->p_size ||
	    params->g_size > params->p_size)
		return -EINVAL;

	/*
	 * Don't permit 'p' to be 0.  It's not a prime number, and it's subject
	 * to corner cases such as 'mod 0' being undefined or
	 * crypto_kpp_maxsize() returning 0.
	 */
	if (memchr_inv(params->p, 0, params->p_size) == NULL)
		return -EINVAL;

	return 0;
}
EXPORT_SYMBOL_GPL(crypto_dh_decode_key);
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
802c7f1c SB	2	/*
	3	* Copyright (c) 2016, Intel Corporation
	4	* Authors: Salvatore Benedetto <[email protected]>
802c7f1c SB	5	*/
	6	#include <linux/kernel.h>
	7	#include <linux/export.h>
	8	#include <linux/err.h>
	9	#include <linux/string.h>
	10	#include <crypto/dh.h>
	11	#include <crypto/kpp.h>
	12
48c6d8b8	13	#define DH_KPP_SECRET_MIN_SIZE (sizeof(struct kpp_secret) + 3 * sizeof(int))
802c7f1c	14
d6e43798	15	static inline u8 dh_pack_data(u8 dst, u8 end, const void src, size_t size)
802c7f1c	16	{
d6e43798 EB	17	if (!dst \|\| size > end - dst)
d6e43798 EB	18	return NULL;
802c7f1c SB	19	memcpy(dst, src, size);
	20	return dst + size;
	21	}
	22
	23	static inline const u8 dh_unpack_data(void dst, const void *src, size_t size)
	24	{
	25	memcpy(dst, src, size);
	26	return src + size;
	27	}
	28
cb195b36	29	static inline unsigned int dh_data_size(const struct dh *p)
802c7f1c	30	{
48c6d8b8	31	return p->key_size + p->p_size + p->g_size;
802c7f1c SB	32	}
802c7f1c SB	33
5b3f3a8b	34	unsigned int crypto_dh_key_len(const struct dh *p)
802c7f1c SB	35	{
	36	return DH_KPP_SECRET_MIN_SIZE + dh_data_size(p);
	37	}
	38	EXPORT_SYMBOL_GPL(crypto_dh_key_len);
	39
	40	int crypto_dh_encode_key(char buf, unsigned int len, const struct dh params)
	41	{
	42	u8 *ptr = buf;
d6e43798	43	u8 * const end = ptr + len;
802c7f1c SB	44	struct kpp_secret secret = {
	45	.type = CRYPTO_KPP_SECRET_TYPE_DH,
	46	.len = len
	47	};
	48
d6e43798	49	if (unlikely(!len))
802c7f1c SB	50	return -EINVAL;
802c7f1c SB	51
d6e43798 EB	52	ptr = dh_pack_data(ptr, end, &secret, sizeof(secret));
	53	ptr = dh_pack_data(ptr, end, &params->key_size,
	54	sizeof(params->key_size));
	55	ptr = dh_pack_data(ptr, end, &params->p_size, sizeof(params->p_size));
d6e43798 EB	56	ptr = dh_pack_data(ptr, end, &params->g_size, sizeof(params->g_size));
	57	ptr = dh_pack_data(ptr, end, params->key, params->key_size);
	58	ptr = dh_pack_data(ptr, end, params->p, params->p_size);
d6e43798 EB	59	ptr = dh_pack_data(ptr, end, params->g, params->g_size);
d6e43798 EB	60	if (ptr != end)
802c7f1c	61	return -EINVAL;
802c7f1c SB	62	return 0;
	63	}
	64	EXPORT_SYMBOL_GPL(crypto_dh_encode_key);
	65
fae19893	66	int __crypto_dh_decode_key(const char buf, unsigned int len, struct dh params)
802c7f1c SB	67	{
	68	const u8 *ptr = buf;
	69	struct kpp_secret secret;
	70
	71	if (unlikely(!buf \|\| len < DH_KPP_SECRET_MIN_SIZE))
	72	return -EINVAL;
	73
	74	ptr = dh_unpack_data(&secret, ptr, sizeof(secret));
	75	if (secret.type != CRYPTO_KPP_SECRET_TYPE_DH)
	76	return -EINVAL;
	77
	78	ptr = dh_unpack_data(&params->key_size, ptr, sizeof(params->key_size));
	79	ptr = dh_unpack_data(&params->p_size, ptr, sizeof(params->p_size));
	80	ptr = dh_unpack_data(&params->g_size, ptr, sizeof(params->g_size));
	81	if (secret.len != crypto_dh_key_len(params))
	82	return -EINVAL;
	83
fae19893 NS	84	/* Don't allocate memory. Set pointers to data within
	85	* the given buffer
	86	*/
	87	params->key = (void *)ptr;
	88	params->p = (void *)(ptr + params->key_size);
	89	params->g = (void *)(ptr + params->key_size + params->p_size);
	90
	91	return 0;
	92	}
	93
	94	int crypto_dh_decode_key(const char buf, unsigned int len, struct dh params)
	95	{
	96	int err;
	97
	98	err = __crypto_dh_decode_key(buf, len, params);
	99	if (err)
	100	return err;
	101
ccd9888f EB	102	/*
	103	* Don't permit the buffer for 'key' or 'g' to be larger than 'p', since
	104	* some drivers assume otherwise.
	105	*/
	106	if (params->key_size > params->p_size \|\|
48c6d8b8	107	params->g_size > params->p_size)
ccd9888f EB	108	return -EINVAL;
ccd9888f EB	109
199512b1 EB	110	/*
	111	* Don't permit 'p' to be 0. It's not a prime number, and it's subject
	112	* to corner cases such as 'mod 0' being undefined or
	113	* crypto_kpp_maxsize() returning 0.
	114	*/
	115	if (memchr_inv(params->p, 0, params->p_size) == NULL)
	116	return -EINVAL;
	117
802c7f1c SB	118	return 0;
	119	}
	120	EXPORT_SYMBOL_GPL(crypto_dh_decode_key);